Computational Prediction of Stall Aerodynamics and Evaluation of Ground Effect for a Generic Transport Aircraft

Flight safety of modern transport aviation depends to a large extent on the skills of the pilot in dealing with manual aircraft control in critical Flight situations.According to Boeing's document " Statistical Summary of Commercial Jet Air-plane Accidents, Worldwide Operations (1959-2016)" about 89 percent of all fatal accidents in aviation take place due to Loss of Control-In Flight (LOC-I), Con-trolled Flight into or Toward Terrain (CFIT), and Runway Excursion (RE). The major contribution to Flight fatalities is related to LOC-I situations when pilots are unable to handle control of an aircraft during an onset of aerodynamic stall at high angles of attack provoking almost unrecoverable Flight conditions. The second contributor to critical flight accidents is related to RE situations during landing and take-o phases of flight. It is now generally accepted that the reduction in accidents can be achieved via improved training of line pilots using modern flight simulators, which are now used for regular pilot training in normal flight conditions. Pilot training in extended flight envelope will soon become mandatory following new regulations from FAA, ICAA and EASA. Training of pilots for upset prevention and recovery in LOC-I critical conditions need flight simulators upgraded with aerodynamic models covering extended flight envelope including high angles of attack with separated low conditions. Flight accidents with RE require improved modeling of aerodynamics in close proximity to the ground considering cross-wind conditions. Data for aerodynamic models for normal and extended flight conditions are traditionally obtained from wind tunnel tests using different methods such as static, forced oscillation and rotary balance tests. The role of Computational Fluid Dynamics (CFD) methods in generating aerodynamic data for extended flight envelope has a significant potential in improving delity of aerodynamics models and reducing the cost of such models. Wind tunnel test results at high angles of attack are sensitive to the level of low turbulence in the tunnel and aero-elastic vibrations of the aircraft model, while computational simulation predictions are highly sensitive to the selection of turbulence model closing the Unsteady Reynolds Averaged Naiver-Stokes (URANS) equations. This Thesis is mostly focused on computational prediction of static stall hysteresis, ground effect and ice accretion effect on aerodynamics of flight which leads to upset of aircraft in the extended flight envelope. The ultimate motive is to generate reliable aerodynamic data which can be used to develop flight models that can be used to train pilots for loss of control of aircraft in critical flight situations